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What is the last digit of: 3^2046? Thanks for help.

 Feb 11, 2017

Best Answer 

 #3
avatar+26396 
+15

What is the last digit of: 3^2046?

 

3φ(10)1(mod10)|φ(10)=10(112)(115)=4341(mod10)32046(mod10)34511+2(mod10)3451132(mod10)(34)51132(mod10)(1)51132(mod10)32(mod10)9(mod10)9

 

The last digit is 9

 

laugh

 Feb 13, 2017
 #1
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Here are the last 10 or so digits........... 2899855929.

 Feb 11, 2017
 #2
avatar+37165 
+5

3^1  = 3

3^2  = 9

3^3  = 27

3^4  =81

3^5  = 243

3^6  = 729

3^7 =2187 

3^8 = 6561

3^9 =19683

3^10=59049

  You might be able to see a pattern of last digits happening here?  (repeating every four?)

 

2046 mod 4 = 2           The second one above is 9    I expect 3^2046   ends in 9.

 Feb 12, 2017
 #3
avatar+26396 
+15
Best Answer

What is the last digit of: 3^2046?

 

3φ(10)1(mod10)|φ(10)=10(112)(115)=4341(mod10)32046(mod10)34511+2(mod10)3451132(mod10)(34)51132(mod10)(1)51132(mod10)32(mod10)9(mod10)9

 

The last digit is 9

 

laugh

heureka Feb 13, 2017

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